Collapsible whipstock



Nov. 23, 1943. J. E. BRANTLY COLLAPSIBLE WHIPSTOCK Filed Nov. 12, 1940 2 Sheets-Sheet l J i 9 w m p g N n a 5 W 1 Nov. 23, 1943.

J. E. BRANTLY COLLAPSIBLE WHIPSTOCK Filed Nov. 12, 1940 2 $heets$heet 2 alented Nov. 23, 1943 2,334,746 COLLAPSIBLE WHIPSTOCK John E. Brantly, Pasadena, Calil'., assignorto Drilling and Exploration Company, Inc., Los Angeles, Calif., a corporation of Delaware Application November 12, 1940, Serial No. 365,141

4 Claims.

This invention has to do with whipstocks for use in oil well drilling, and comprises as to general form, an elongated body adapted to be carried on the lower portion of a pipe string above a bit or other tool, and used to deflect the tool as drilling proceeds and thereby change the direction of the well bore from the particular course taken above the whipstock.

The customary practice is to lower and set the whipstock in proper position, and to then continue drilling at an angle from the previous course of the well, as determined by the deflection given the bit and drill pipe by the Whipstock. The course of the well bore may be so deflected for various reasons, as to reach ultimately a predetermined production zone, or to drill around objects irretrievably lodged in the well. After completion of the whipstock drilling, the pipe string is pulled to remove the whipstock from the well. It frequently happens that the whipstock itself has become so tightly lodged in the well, as by formation imbedding or com-v pacting against the whipstock, as to render the latter removable, if at all, only with difiicultyand imposition of excessive strains on the drill pipe, or by the use of special equipment and operations.

My primary object is to provide an improved whipstock construction adapted to facilitate and assure ready removability of the tool regardless of how tightly it may have become lodged in the well by lateral formation pressure or by cavings or by cuttings (all of which are included in the term formation). Generally speaking, this object is accomplished by giving the whipstock collapsible characteristics in that it is laterally contractible to produce a substantial reduction in its transverse dimension. Thus, should the tool become so tightly impedded in the forma tion as to interfere with its removability, it may be laterally contracted to relieve the formation or caving or cuttings pressure against it and permit the tool to be readily withdrawn. Another feature of the invention is the capacity of the whipstock at all times to remain in a normally or laterally expanded condition and to be subject to or capable of lateral contraction only when it becomes lodged in the well.

The various specific forms of whipstocks contemplated by the invention may be described generally as comprising a plurality of longitudinally extending sections capable of relative contractive movement along interengaging inclined or wedge surfaces. As will later appear, the tool may comprise two or more of such relatively movable sections that may be arranged to give different degrees of radial or circumferential contractibility, according to the particular design preferred. For most purposes, I prefer to construct the tool with one main body section running its full length, and to provide one or more shorter sections movable downwardly relative to the body section and along an inclined surface, or along individual surfaces, to produce lateral contraction of the tool. Normally, the movable section or sections may be releasably held by suitable means such as one or more shear pins. The whipstock is self-collapsible when lodged in the formation, simply by upward pull on the drill string to sever the shear pin and thereby permit the body section of the tool to move upward and away from the then inwardly movable complementary section.

The various features and objects of the invention, together with the details of certain typical and illustrative embodiments, will be understood to better advantage from the detailed description to follow. Reference is had throughout the description to the accompanying drawings in which:

Fig. 1 is a view taken in longitudinal section showing one form of the invention;

Fig. 2 is an enlarged cross-section on line 2-2 of Fig. 1;

Fig. 3 is a fragmentary longitudinal section showing a variational form of key interconnecting the relatively movable parts of the whipstock;

Fig. 4 is an enlarged cross-section on line 4-4 of Fig. 3;

Fig. 5 is a side elevation of a variational form of the invention employing a pair of wedge sections similar generally to the single section of Fig. 1;

Fig. 6 is an enlarged cross-section on lines 6-6 of Fig. 5;

Fig. 7 is a side elevation of a further variational form of the invention;

Fig. 8 is an elevation viewing Fig. '7 from the right;

Figs. 9 and 10 are enlarged cross-sections on lines 99 and Ill-l0 of Fig. 7;

Fig. 11 illustrates another variational form having three superposed, relatively movable sections; and

' Fig. 12 is a cross-section on line 12-42 of Fig. 11.

It will be understood that aside from the sectional construction of the tool giving it collapsible characteristics, the general form of the tool may be as desired. Typically, I have shown the tool in Fig. 1 to comprise an elongated body,

.been set and drilling then, proceeds.

The body may be regarded as including a second and relatively movable section lb that may, and preferably does, extend beyond half the length of the tool from its lower end, in order to render the body laterally contractible throughout the length required to release it from the formation under all ordinary conditions. Body sections Illa and 10b interengage along inclined or wedge surfaces l5 which may exactly or generally parallel the base of recess l4. Section Ill-b carries a dovetail tongue 16 projecting within an undercut groove or way l1 milled longitudinally in the adjacent face of section Illa, which guide the sections in their relative movement and maintain them at all positions, in engagement along surfaces l5. Body section lllb normally is held in the position of Fig. 1, in which it engages a stop shoulder l8 on section Illa, by means of a shear pin 19, adapted to be severed by upward pull exerted on section Illa, as will presently appear. The sections are retained in engagement permitting relative longitudinal movement, by a suitable key which may consist simply of a strong pin 20 inserted through slots 2| and 22 in section I01), and threaded at 23 into section Illa. Movement apart of the sections is prevented by engagement of the flanged pin head 200. with surface 24 between slots 2| and 22. As will be apparent, engagement of section lllb with body shoulder I8, and the engagement of key It with shoulder 25, relieve pin l9 against strain as a result of downward forces applied through body section Illa. If desired, slot 2| may be closed by a plate 2 to prevent the entry of solids that might interfere with movement of pin 20.

Figs. 3 and 4 illustrate a variational form of key connection between the body sections. Here the key proper comprises a sliding element or plate 26 placed within a recess 21 in body section Illa, and having integrally formed or attached thereto as by welding, a pin 28. In assembling the key structure within the body sections, plate 26 is put into recess 21 and a plate 29 containing a slot 30 through which pin 28 passes, is placed over the key 26 and welded within recess 21. Section lllb is then applied in the position of Fig. 1 by placing opening 3| over the pin 28 and welding the section to the pin as at 32. A suitable lubricant may be introduced to slot 30 and the unoccupied portion of slot 21, through passages 33 and 34 in the pin 28, as best shown in Fig. 4. As will be understood, the sections Illa. and l 0b normally will be held against relative movement by a shear pin as at 19 in Fig. 1.

The tool normally will be used in the condition shown in Fig. 1, and in fact it will remain in that condition during all operations unless it becomes lodged in the well so as to require 001- lapsing to facilitate its removal. While being lowered and set within'the well, the whipstock may be held against rotation relative to the pipe string, by any suitable mean such as a spot weld at W or a shear pin S, either of which may be broken or sheared after the tool is set and drilling is to proceed. by lowering the pipe string. Assuming that after whipstock drilling-the tool has become imbedded in formation exerting such lateral pressure against the body It as to prevent or seriously interfere with its withdrawal, the tool may readily be freed simply by exerting sufllcient pull on the pipe string toshear pin l8 and permit upward movement of the main body section Illa relative to section 10b. Due to the angularity of the interengaging surfaces I5 of the members, upward movement of section Illa in effect reduces the transverse dimension of the body assembly, permitting it to move away from or reduce its pressure against the formation, to the point that the tool can be withdrawn without difliculty. Section lllb is of course prevented from moving upwardly, due to its weight and its engagement with the formation. When key pin 20 reaches the upper end of slot 22, or in the formof Fig. 3, when the bottomshoulder 21a of slot 21 engages the lower end of key 26, section lb of the body then is carried upwardly and withdrawn together with the main body section. Finally it may be observed in connection with the described form of the invention, that the interengaging surfaces l5 may have any desired angularity depending upon the extent to which the tool is to be laterally contractible.

The form of the invention shown in Fig. 5 is 38 as in Fig. 1. As will be observed from Fig. 6,

section I00 and lb may together extend in excess of about the body, with the advantageous result that the tool thereby becomes laterally or radially contractible over a corresponding portion of its circumference. This permits release of the tool regardless of the circumferential distribution of lateral formation pressures, since the tool is laterally contractible across all diameters.

The form of the invention illustrated in Figs. '1 to 10 differs from those previously described in that instead of the wedge sections being applied to a surface of the main body section opposite its longitudinal recess, the body of the tool is, in effect, split longitudinally along an inclined surface generally normal to the guide recess, and. is made in sections movable relatively alon such inclined surface. Viewing the tool in the aspect of Fig. 8 (looking into the guide recess 42) the body 43 is divided along angular or wedge surfaces 44, into a main section 43a and a wedge section 43b attached to the former section by shear pin 45. Section 431) carries a spline 46 projecting within groove 41 in section 430., and as in Figs. 1 and 5, limited relative movement of section 43a upwardly relative to section 431) after shearing of pin 45 is permitted by pin 48 extending through a slot 49 in section 4312 and threaded at 50into the main body section.

The final form of the invention shown in Figs. 11 and 12 is characterized by the provision of a plurality in excess of two, of relatively longitudinally movable sections that may be employed to give the tool a eater degree of transverse contractibility by reason of the multiplicity ofwedge engaging sections. Any suitable number of such sections may be used in this construction, three being shown as typical. Applied directly to the main body section and inengagement therewith along inclined surface 52, is an intermediate section 53 releasably held in its normal position by shear pin 54. A spline 55 on section 53 projects within way 56 in'the main section 5i, and the two sections are held together permitting their relative movement, by pins 51 threaded into section 5| through slots 58 and 59. A third wedge section 60 engaging the outside of section 53 along inclined surfaces 6| paralleling surfaces 52, has a spline 63 working within way M, and is releasably attached to section 53 by shear pin 65. Sections 53 and 60 are held togetherto permit their relative movement, by pin 88 inserted through slots 61 and 68.

Upward pull on the main body section 5| when the tool becomes lodged, may shear either or both of pins 54 and 65, permitting relative movement of any two or all three of the body sectiona'as the case my be. The tendency for both pin 65 and 54 to shear will of cours increase according to the tightness with which the body is lodged in the well. And accordingly, the greater will be the capacity of the tool for freeing itself from the formation by reason of the increased contractibility permitted by relative movement of all three sections.

I claim:

1. A retrievable well whipstock comprising a body having a pair of sections that are relatively movable to transversely contract th body and thereby facilitate its removal from the well, and means connecting said sections to maintain the body in transversely expanded condition while it is being lowered in the well, said connecting means thereafter being releasable to permit said bodycontracting relative movement of the sections.

2. A retrievable whipstock comprising a transthe whipstock from the versely contractible body adapted .to be lowered and set in a well in transversely expanded condition, said body including a pair of vertically elongated oppositely disposed wedge sections that are relatively vertically movabl by an upward pull on one section, when the body becomes lodged in the formation, to contract the body transversely and thereby facilitate it removal from the well, and a connection between said sections holding them against body contracting relative movement while the body is being lowered in the well, said connection being adapted to be released by stresses tending to mov one section vertically relative to the other section.

3. A retrievable whipstock for use in a well, comprising a body section and a vertically elongated wedge section engaging the body along an inclined surface, means for connecting said body section to a pipe string, and a shear pin normally holding said sections against relative vertical movement to maintain the whipstock in transversely expanded condition, said pin being shearable by stresses tending to move the body section vertically relatively to the wedge section.

4. A whipstock comprising a portion having a tool-guiding face, a portion backing said toolguiding portion and forming therewith an enlargement of the lower part of the whipstock, and means for securing said portions together to provide such enlargement of the lower part of the whipstock. the enlargement of the lower part of the whipstock in comparison with the upper part thereof being primarily due to said backing portion so that when the tool-guiding portion is free to move upwardly relatively to the backing portion the former may be readily withdrawn from a hole, said securing means releasing said portions for said movement of the tool-guiding portion upwardly relatively to the backing portion under stresses tending to prevent removal oi hole.

JOHN E. BRANTLY. 

